[francisdavey]

I strongly recommend Dixon's The Rise and Fall of Languages (https://www.amazon.co.jp/-/en/Dixon/dp/0521626544) for a slightly contrary view. His experience with Australia suggests that languages can exist in equilibria for long periods of time with considerable borrowing of not only words but other language features so that after a long time you can't really usefully identify any evolutionary tree.

What happens, he suggests, is occasionally you have significant events which cause one, or sometimes several closely located, languages to spread widely and then you can see a family tree over that period of time. For example: Indo-European. What you can't hope to do is to go back tens of thousands of years.

Obviously he sees things through the filter of Australian linguistics, but he did some excellent fieldwork (which is also very interesting, though it may be out of print) and produced a wonderful monograph on Dyirbal (of "women, fire and dangerous things" fame).

[Projectiboga]

Wow, that guy is quite the published expert. I looked him up, that possibly out of print one is available. https://annas-archive.org/search?q=R.%20M.%20W.%20Dixon